the opening statements in a case we've been following closely here on "gma." The high school valedictorian accused of killing his own mother. The young man so popular in his hometown, the judge had a problem empaneling an impartial jury. Reporter: He's a beloved figure in his community, all-around good guy. Jeffrey pyne says he didn't kill his mother. His surviving family says he didn't do it. But prosecutors began making their case. Jeffrey pyne sat expressionless, as prosecutors told the jury how he bludgeoned, stabbed a killed his mother, ruth. He hit her. And he hit her again. And again. Reporter: Played in court, 911 tapes of the horror witnessed by jeffrey pyne's father and sister, who found ruth pyne's body. I don't know what's going on. Okay. Is she in the house or outside? She's in the garage. Reporter: Prosecutors contend jeffrey pyne killed his mother in anger from years of abuse. Ruth pyne was bipolar and violent. She was arrested for beating and choking her son just nine months before her death. The defense maintains jeffrey pyne is innocent. Somebody else committed this crime. We believe the evidence will show you that. Reporter: But prosecutors showed some startling evidence of their own. Photos of blisters on jeffrey's hands, hours after the murder. He said he got them throwing a shipping pallet. I expect a splinter or scrape, other than what looked like a rope burn. Reporter: The blisters are expected to be the focal point of the prosecution's evidence. But with his own family saying he's innocent and the community at large firmly in jeffrey pyne's corner, will it be enough for a conviction? This is a tough case for prosecutors. Not only is the physical evidence limited, but you have a really sympathetic defendant. Reporter: The trial could last two to three weeks. No word from the defense if jeffrey pyne will ta stand in his own defense. If convicted, he could face life in prison without parole.

This transcript has been automatically generated and may not be 100% accurate.

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